CN107698429B - A kind of method of functionalized ion liquid catalytic synthesis of bisphenol fluorene - Google Patents

A kind of method of functionalized ion liquid catalytic synthesis of bisphenol fluorene Download PDF

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CN107698429B
CN107698429B CN201710876619.2A CN201710876619A CN107698429B CN 107698429 B CN107698429 B CN 107698429B CN 201710876619 A CN201710876619 A CN 201710876619A CN 107698429 B CN107698429 B CN 107698429B
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phenol
ionic liquid
bisphenol fluorene
cation
catalytic synthesis
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CN107698429A (en
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于丽梅
高占先
罗世康
闫磊
申茂昌
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Dalian University of Technology
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    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C37/00Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
    • C07C37/11Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms
    • C07C37/20Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring by reactions increasing the number of carbon atoms using aldehydes or ketones
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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Abstract

The invention discloses a kind of methods of catalytic synthesis of bisphenol fluorene, using phenol and 9-Fluorenone as raw material, using proton acidic functionalized ionic liquid as catalyst, carry out condensation reaction;The proton acidic functionalized ionic liquid is made of anion and cation;The cation is benzothiazolyl cation or benzimidazolyl cation;The anion is HSO4 、H2PO4 、BF4 、Tos.The method of the present invention is using phenol and Fluorenone as raw material, and under proton acidic functionalized ionic liquid catalytic action, easy to operate, the reaction time is short, small to equipment corrosion, and reaction conversion ratio reaches 100%, and product purity is very high after recrystallization.Entire reaction process does not need co-catalyst, is thus avoided that and causes worker's poisoning and air pollution in production process.In addition to this, proton acidic functionalized ionic liquid and phenol are by being evaporated under reduced pressure equal recoverable, and greatly reduce the pollution of phenol and the concentrated sulfuric acid to environment.

Description

A kind of method of functionalized ion liquid catalytic synthesis of bisphenol fluorene
Technical field
The present invention relates to bisphenol fluorene preparation fields, and in particular to a kind of functionalized ion liquid catalytic synthesis of bisphenol fluorene Method.
Background technique
Bis- (4- hydroxyphenyl) fluorenes of bisphenol fluorene i.e. 9,9-, molecular formula C25H18O2, molecular weight 350.4,222 DEG C of fusing point~ 224 DEG C, white powder substance dissolves in the organic solvents such as acetonitrile, toluene, methanol, isopropanol, methylene chloride.
It is raw material in the presence of acidic through Cardo prepared by condensation reaction that bisphenol fluorene, which is using Fluorenone and phenol, The bisphenol compound of ring skeleton structure.In modern polymerization process industry, bis-phenol fluorene compound and its substitutive derivative conduct Important monomer is largely used to condensation reaction, particularly for prepare high temperature resistant, good luster performance, high flame resistance The polycondensation products such as polycarbonate, polyurethane, polyethers.The polycondensation products as made from bisphenol fluorene can be used as heat proof material, photosensitive material Material, electrical conductor material and high-temperature resistant coating etc., are widely used in the fields such as aircraft, space flight and aviation, automobile, military affairs, electronics It is widely used.
Different according to used catalyst, the method for the bisphenol fluorene synthesizing of existing patent literature report is as follows at present It is shown:
(1) synthetic method reported in U.S.Pat.No.4675458: being starting material and phenol in dense sulphur using 9-Fluorenone Under acid catalysed conditions, bisphenol fluorene synthesizing, yield is about 85%, but a large amount of phenol wastewater are generated in this method washing process, to ring Border causes seriously to pollute, and processing is difficult.Therefore, which is eliminated substantially.
(2) synthetic method reported in U.S.Pat.No.5149886: being starting material and phenol in chlorination using 9-Fluorenone Hydrogen is as bisphenol fluorene synthesizing under catalytic condition, yield 85%, but hydrochloride aqueous solution corrosivity is strong, to damage of facilities Greatly, and production operation is cumbersome, and security risk is big.
(3) synthetic method reported in Chinese invention patent application prospectus CN1617845: in 9-Fluorenone, benzene Phenol, strong-acid ion exchange resin and mercaptopropionic acid catalytic synthesis of bisphenol fluorene, catalyst is recyclable, it is small to corrode to equipment;But it is anti- Long between seasonable, catalyst is at high cost.
(4) research [J] Chemical Engineer of Gao Qingping, Wang Wenzheng Catalyzed by Phosphotungstic Acid bisphenol fluorene synthesizing, 2009, 23 (6): the synthetic method reported in 12-13: heteropoly acid bisphenol fluorene synthesizing is applied, bisphenol fluorene yield is 65.3%, although can It realizes catalyst recycling but catalyst is at high cost, the reaction time is long, and needs co-catalyst.
(5) research [D] that Shen Maochang .Bronsted presence of acidic ionic liquid catalyst 9-Fluorenone is reacted with phenol condensation, Dalian Polytechnics, 2015, the synthetic method of middle report: using 9-Fluorenone and phenol as raw material, urged in functionalization acidic ionic liquid plus help Bisphenol fluorene synthesizing under the conditions of agent, this method conversion ratio can reach 100% and catalyst is easy recycling and reusing, but whole process Need to consume co-catalyst mercaptan carboxylic acid, mercaptan carboxylic acid is with foul smell and has severe toxicity, and price is relatively high.
Summary of the invention
Insufficient in the prior art in order to overcome, the present invention provides a kind of functionalized ion liquid catalytic synthesis of bisphenol fluorene Method, this method reaction time is short, and reaction conversion ratio is up to 100%, and solid crude product yield is up to 95%, does not need to help and urge Agent, it is small to equipment corrosion, and catalyst and the equal recoverable of phenol, it is low in the pollution of the environment, production cost is reduced, is suitble to The preparation method of industrialized production.
The technical scheme adopted by the invention is that a kind of method of catalytic synthesis of bisphenol fluorene, is original with phenol and 9-Fluorenone Material carries out condensation reaction using proton acidic functionalized ionic liquid as catalyst;
The proton acidic functionalized ionic liquid is made of anion and cation;
The cation is benzothiazolyl cation [(CH2)3SO3HBth]+Or benzimidazolyl cation [(CH2)3SO3HBim]+
Its structural formula are as follows:
The anion is HSO4 -、H2PO4 -、BF4 -、Tos-
Cation is preferably benzothiazolyl.
Most preferably, the proton acidic functionalized ionic liquid is [(CH2)3SO3HBth][HSO4]。
As a preferred technical solution, in the condensation reaction, the molar ratio of phenol and 9-Fluorenone is 1:4~1:10,9- The molar ratio of Fluorenone and proton acidic functionalized ionic liquid is 1:0.1~1:0.45.
The condition of the condensation reaction is 60~150 DEG C of temperature as a preferred technical solution, and the reaction time 2~10 is small When.
It is highly preferred that 90~110 DEG C of reaction temperature, the reaction time 4~6 hours.
In condensation reaction, phenol is not only used as reactant, but also as reaction dissolvent.
Preferred 5:1~the 8:1 of the molar ratio of the phenol and 9-Fluorenone, 9-Fluorenone and proton acidic functionalized ionic liquid Preferred 1:0.3~the 1:0.4 of molar ratio, the ratio can be such that 9-Fluorenone 100% converts.
The method also includes being filtered and obtained using washing, decompression after condensation reaction as a preferred technical solution, After solid product, then methylene chloride is used to recrystallize the solid product.
The recrystallization solvent can also be any one of ethyl alcohol, isopropanol, methanol, methylene chloride, acetone, The present invention is preferably methylene chloride.
Decompression filters to obtain solid particulate matter and filtrate, and solid particulate matter is dry to get the crude product for arriving bisphenol fluorene, Gu Body yield is up to 95%.Bisphenol fluorene, product yield about 89% are recrystallized to obtain, purity is greater than 99%.
The washing is the water washing for first using 5~25 DEG C as a preferred technical solution, obtains water phase A and solid phase A;Again The solid phase A is washed using 70~90 DEG C of water, obtains aqueous phase B and the solid product.The mesh of 5~25 DEG C of water washings Be recycle proton acidic functionalized ionic liquid, the purpose of 70~90 DEG C of water washings be recycle phenol, so as to Bronsted acid function Further recycling for ionic liquid and phenol can be changed.
The method also includes being recycled after re-crystallization as a preferred technical solution, comprising the following steps: subtracts Pressure distills the water phase A and recycles proton acidic functionalized ionic liquid, is evaporated under reduced pressure the aqueous phase B recycling phenol.
It is highly preferred that at room temperature, the mixed liquor that condensation reaction obtains is poured into beaker while hot, it is added in beaker suitable 5~25 DEG C of water washings, stratification are measured, upper layer is water phase, and lower layer is oily sticky solid.It separates water phase and oily is sticky solid Body phase, acidic functionalized ionic liquid containing proton and a small amount of phenol in water phase are to be processed;In oily sticky solid be added 70~ 90 DEG C of hot water, are stirred, stratification with glass bar, and upper layer is water phase, and lower layer is still oily sticky solid, separation water phase and oil Shape sticky solid phase repeats aforesaid operations, until plus stir after removing 90 DEG C of hot water, solid phase is no longer sticky, and solid becomes It is granular, stop aforesaid operations.70~90 DEG C of water phases for depressurizing the filtrate filtered and washing oily sticky solid merge, through depressurizing Water is distilled off and collects to obtain phenol, phenol recovery rate is up to 80%.
Detailed description of the invention
Fig. 1 is the liquid chromatogram of 1 distillate sample of embodiment;
Fig. 2 is the influence that Pyrogentisinic Acid and Fluorenone condensation reaction is recycled in 1 ionic liquid of embodiment.
Specific embodiment
Embodiment 1
Ionic liquid [(CH2)3SO3HBth][HSO4] preparation in preparation method, it is specific the preparation method is as follows: will The benzothiazole of 0.2mol is added in the three-necked flask of 100mL, and 30mL dehydrated alcohol is added in three-necked flask, constantly stirs It mixes down, the 1,3-propane sultone of equimolar amounts is added dropwise into reaction flask with constant pressure funnel;After completion of dropwise addition, it is warming up to 90 DEG C of reaction 4h.After reaction, it is washed respectively three times with acetone and ether 20mL, vacuum at filtered filter cake and 80 DEG C Dry 6h, obtains intermediate amphoteric ion.The amphoteric ion intermediary of 5g is added in the round-bottomed flask of 50mL, adds the water of 20mL For solvent, the sulphur of equimolar amounts is slowly added dropwise, pays attention to stirring during being added dropwise.After completion of dropwise addition, 80 DEG C of heating water bath, instead 6h is answered, after reaction, removes water with revolving first, then washed three times with 15mL ether.Obtained crude product vacuum at 80 DEG C is dry Dry 6h obtains ionic liquid [(CH2)3SO3HBth][HSO4], nuclear magnetic data is as follows:1H NMR(400MHz,D2O, TMS): δ (ppm):8.98(s,1H),8.18-8.06(m,2H),7.82-7.76(t,1H),7.74-7.25(t,1H), 4.81(t,2H), 2.93(t,2H),2.42-2.27(m,2H)。
The preparation of bisphenol fluorene: accurately weighing a certain amount of Fluorenone, is added into the three-necked flask of 50mL, is then added suitable The phenol of amount, ionic liquid [(CH2)3SO3HBth][HSO4], at one 90 DEG C, heating, reflux 6h uses glass after reaction Glass stick dips suitable reaction solution and is dissolved in CH3In OH, analyzed it with liquid chromatogram.Reaction solution is poured into beaker while hot In, appropriate 20 DEG C of water is added in beaker and is washed, stratification, upper layer is water phase, and lower layer is oily sticky solid.Point From water phase and oily sticky solid phase, ionic-liquid catalyst and a small amount of phenol are contained in water phase, it is to be processed;It is sticky solid in oily 90 DEG C of hot water are added in body, are stirred with glass bar, stratification, upper layer is water phase, and lower layer is still oily sticky solid, separation Water phase and oily sticky solid phase repeat aforesaid operations, until plus stir after removing 90 DEG C of hot water, solid phase is no longer sticky, solid Become graininess, stops aforesaid operations.Decompression filters, and obtains solid particulate matter and filtrate, and solid particulate matter drying is arrived The crude product of bisphenol fluorene, solid yields 94%.Bisphenol fluorene is recrystallized to obtain, bisphenol fluorene yield 89%, product purity is greater than 99%.Nuclear magnetic data is as follows:1H NMR (400MHz, Chloroform-d) δ 7.75 (dt, J=7.4,1.0Hz, 2H), 7.39- 7.31(m,4H),7.30–7.23(m,2H),7.09–7.03 (m,4H),6.70–6.64(m,4H).13C NMR(101MHz, Chloroform-d)δ154.19, 151.71,139.93,138.30,129.37,127.68,127.34,125.98, 120.13,114.98.The water phase of the filtrate that decompression is filtered and 90 DEG C of washing oily sticky solids merges, and removes through vacuum distillation Water is gone to collect to obtain phenol, phenol recovery rate is up to 80%, by 30 DEG C of water phase vacuum distillation recycling ionic liquid, so as to ion Liquid and phenol further recycle.By efficient liquid phase chromatographic analysis, as shown in Figure 1, reaction conversion ratio is 100%.
The circulation experiment of catalyst ion liquid: accurately weighing a certain amount of Fluorenone, is added to the three-necked flask of 50mL In, suitable phenol is then added, ionic liquid, at a certain temperature, heating flow back a few hours, after reaction, return Receive ionic liquid;Examine [(CH2)3SO3HBth][HSO4] be recycled effect.Specific experiment operation is as follows: reacting After, quantitative deionized water is added into reaction flask, stirs, static layering, supernatant liquid is transferred to 50mL single neck round bottom In flask, revolving water removal is washed 3 times with ether, is reused after being dried in vacuo 2-3h at 100 DEG C, recycles five catalysis Activity is without being decreased obviously, as shown in Figure 2.
Above embodiments are preferable implementation process of the invention, not do more limitation to the present invention.All foundations Simple modification or equivalent variation and modification are made to technological essence of the invention, still belong to the scope of protection of the invention.

Claims (6)

1. a kind of method of catalytic synthesis of bisphenol fluorene, which is characterized in that using phenol and 9-Fluorenone as raw material, with proton acid functionalization Ionic liquid is catalyst, carries out condensation reaction;
The proton acidic functionalized ionic liquid is made of anion and cation;
The cation is benzothiazolyl cation or benzimidazolyl cation;
The anion is HSO4 -、BF4 -、OTs-
2. the method for catalytic synthesis of bisphenol fluorene according to claim 1, which is characterized in that in the condensation reaction, phenol Be 1:4~1:10 with the molar ratio of 9-Fluorenone, the molar ratio of 9-Fluorenone and proton acidic functionalized ionic liquid be 1:0.1~ 0.45。
3. the method for catalytic synthesis of bisphenol fluorene according to claim 1, which is characterized in that the condition of the condensation reaction is 60~150 DEG C of temperature, the reaction time 2~10 hours.
4. the method for catalytic synthesis of bisphenol fluorene according to claim 1, which is characterized in that the method also includes being condensed After reaction, filtered using washing, decompression after obtaining solid product, then the solid product is tied again using methylene chloride It is brilliant.
5. the method for catalytic synthesis of bisphenol fluorene according to claim 4, which is characterized in that the washing be first using 5~ 25 DEG C of water washing obtains water phase A and solid phase A;The solid phase A is washed using 70~90 DEG C of water again, obtains aqueous phase B and institute State solid product.
6. the method for catalytic synthesis of bisphenol fluorene according to claim 4 again, which is characterized in that the method also includes tying It is recycled after crystalline substance, comprising the following steps: be evaporated under reduced pressure the water phase A recycling ionic liquid, be evaporated under reduced pressure the phase B recycling benzene Phenol.
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CN108250049B (en) * 2018-03-25 2021-04-27 明天塑料(上海)有限公司 Synthesis method of bisphenol fluorene
CN108570019B (en) * 2018-05-31 2021-02-26 大连理工大学 Acidic ionic liquid and catalytic application thereof
CN116444345A (en) * 2023-04-25 2023-07-18 郑州中科新兴产业技术研究院 Method for preparing fluorenyl dihydric alcohol by utilizing sulfonic acid type ionic liquid catalysis
CN116444346A (en) * 2023-04-25 2023-07-18 郑州中科新兴产业技术研究院 Method for synthesizing bisphenol compound by catalysis of supported ionic liquid

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1986509A (en) * 2006-12-20 2007-06-27 哈尔滨工程大学 Bisphenol fluorene synthesizing process catalyzed with solid supported heteropolyacid
CN101003466A (en) * 2007-01-19 2007-07-25 哈尔滨工程大学 Method for synthesizing bisphenol fluorine by catalysis of highly acidic cation exchange resin
CN105152867A (en) * 2015-05-03 2015-12-16 上虞日月星科技化学有限公司 Bisphenol fluorene compound and preparation method thereof
CN105693475A (en) * 2016-03-15 2016-06-22 辽宁大学 Technology method for utilizing solid acid H2SO4-SiO2 for catalyzing and preparing bisphenol

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1986509A (en) * 2006-12-20 2007-06-27 哈尔滨工程大学 Bisphenol fluorene synthesizing process catalyzed with solid supported heteropolyacid
CN101003466A (en) * 2007-01-19 2007-07-25 哈尔滨工程大学 Method for synthesizing bisphenol fluorine by catalysis of highly acidic cation exchange resin
CN105152867A (en) * 2015-05-03 2015-12-16 上虞日月星科技化学有限公司 Bisphenol fluorene compound and preparation method thereof
CN105693475A (en) * 2016-03-15 2016-06-22 辽宁大学 Technology method for utilizing solid acid H2SO4-SiO2 for catalyzing and preparing bisphenol

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"Bronsted酸性离子液体催化9_芴酮与苯酚缩合反应的研究";申茂昌;《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》;20170315(第3期);B014-134 *
"离子液体中烷基化反应和缩合反应的研究";胡燚;《中国优秀博硕士学位论文全文数据库 (博士) 工程科技Ⅰ辑》;20051215(第8期);B014-11 *

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